1. Field of the Invention
The present invention relates to a track member for a track of a tracked vehicle.
2. Description of the Related Art
Tracked vehicles such as, for example, hydraulic excavators, bulldozer, or the like, are provided with handling tracks suitable to allow them to move on broken or steep grounds with ease and controllability.
The tracks comprise articulations of tracks in which inner and outer track links, or portions of inner and outer offset track links, are interconnected on two track sides at predetermined intervals, and are assembled in respective track shoes arranged on the ground contact side. The inner and outer track links are endlessly interconnected by track members acting as connecting members.
To the aim of implementing the above-mentioned connection between track links, several types of track members are known.
An example of track member is described in the U.S. Pat. No. 5,183,318.
Such track member comprises a pin and a bushing that is rotatable relative to such track. The inner track links include inner rings rotatably connected to the pin, and the very track links, which are secured in a rotatingly integral manner, for example, by pressure, on the rings. Instead, the outer track links are secured in a rotatingly integral manner to the pin at external positions of the latter.
Between the inner track links and the pin, first inner gasket seats receiving first gaskets are defined, while between the outer track links and the pin second gasket seats receiving second gaskets are defined. The gaskets act so as to prevent the leakage of lubricant material that is necessary to allow, with reduced wear, the rotations of the bushing relative to the pin and the rings relative to the pin.
Inner spacer members acting between the rings and the bushing are arranged in the inner gasket seats, while outer spacer members acting between the rings and the outer track links are arranged in the outer gasket seats.
However, such track members according to the prior art are not free from drawbacks.
In use, the track members are generally subjected to very high loads. Due to their configuration, in the track members according to the described prior art, the axial loads generated in use by the inner track links and the outer track links completely discharge on the inner spacer members acting between the bushing and the rings. Therefore, the inner spacer members have to be so dimensioned as to be able to withstand such high loads. This involves overall dimensions due to the sizing of the inner spacer members, which are received in inner gasket seats which also will have to be dimensioned while taking into account the dimensions of the spacer members.
A further drawback of the track members according to the prior art consists in that, in use, the pin tends to slip off the track links. In order to obviate this, it is necessary to provide for additional members, such as retaining rings, pegs, or the like.